Field of the Invention
The present invention relates to an electro-pneumatic braking system for a railway vehicle.
Background
More specifically, the present invention relates to an electro-pneumatic braking system comprising                a pneumatic pressure supply pipe,        generator means for generating vehicle load or weight signals,        weighting means designed to supply a weighted pneumatic pressure which defines a maximum braking pressure, limited as a function of the load signals, and        braking control means connected to the weighting means and comprising a relay valve connected between said pipe and (at least) one brake cylinder, to cause the application to said cylinder of a controllable braking pressure, equal to or less than said weighted pressure.        
Electro-pneumatic braking systems of this type are well known, and are described, for example, in patent applications EP 0 958 980 A and WO 2013/144543 A.
There is a general and constant tendency towards the reduction of the size and overall dimensions of these braking systems.
In particular, there is a tendency to construct these systems in the form of line replaceable units (LRU) to allow fast and simple maintenance.
These objectives imply an increased use of electronic and electro-pneumatic systems, in place of the conventional pneumatic componentry which was rather heavy and bulky.
In an electro-pneumatic braking system of the aforesaid type, load signals are generated, indicating the load or weight of the whole vehicle or a part thereof, for example according to whether the braking system is intended to apply the brakes on a vehicle-by-vehicle basis, or on a bogie-by-bogie basis.
In addition to the weighting means and the service braking control means, an electro-pneumatic braking system of this type usually comprises means for controlling the anti-wheel-slip function, designed to block and then reduce the fluid pressure, and subsequently reapply it to the brake cylinders as a function of information supplied by speed sensors associated with the wheels, to resolve situations of wheel locking and slippage.
In some cases, the braking control means and the anti-wheel-slip control means are implemented in a single electronic control unit.